Add circleci config

.circleci/config.yml

@@ -0,0 +1,28 @@
+version: 2
+jobs:
+  build:
+    docker:
+      - image: circleci/node:latest
+
+    working_directory: ~/repo
+
+    steps:
+      - checkout
+
+      - restore_cache:
+          keys:
+          - v1-dependencies-{{ checksum "package.json" }}
+          - v1-dependencies-
+
+      - run: yarn install
+
+      - save_cache:
+          paths:
+            - node_modules
+          key: v1-dependencies-{{ checksum "package.json" }}
+
+      - run: yarn lint
+
+      - run: yarn test --coverage
+
+      - run: yarn coveralls